Atherosclerosis is the most common cause of chronic arterial occlusive disease of the lower extremities. The arterial narrowing or obstruction that occurs as a result of the atherosclerotic process reduces blood flow to the lower limb during exercise or at rest. A spectrum of symptoms results, the severity of which depends on the extent of the involvement and the available collateral circulation. Thus, symptoms may range from intermittent claudication to pain at rest. Intermittent claudication denotes pain that develops in the affected limb with exercise and is relieved with rest. This pain usually occurs distal to the arterial narrowing or obstruction. Since the superficial femoral and popliteal arteries are the vessels most commonly affected by the atherosclerotic process, the pain of intermittent claudication is most often localized to the calf. The distal aorta and its bifurcation into the two iliac arteries are the next most frequent sites of involvement. Narrowing of these arteries may produce pain in the buttocks or the thighs as well as the legs.

Epidemiological studies indicate that up to 5% of men and 2.5% of women 60 years of age or older have symptoms of intermittent claudication.1 2 The prevalence is at least threefold higher when sensitive noninvasive tests are used to make the diagnosis of arterial insufficiency in asymptomatic and symptomatic individuals.3 The symptoms of chronic arterial insufficiency of the lower extremities progress rather slowly over time. Thus, after 5 to 10 years, more than 70% of patients report either no change or improvement in their symptoms, while 20% to 30% have progressive symptoms and require intervention, and less than 10% need amputation.4 5 Despite the relatively benign prognosis for the affected limb, however, symptoms of intermittent claudication should be viewed as a sign of systemic atherosclerosis. This explains why, compared with …

Diagnosis and Treatment of Chronic Arterial Insufficiency of the Lower Extremities: A Critical Review

The duplex ultrasonic scanner combines real-time B-mode imaging with a single-gate, variable-range pulsed Doppler. The detection and categorization of the severity of carotid artery atherosclerosis is achieved by performing spectral analysis of the pulsed Doppler velocity signal obtained from vessels of interest. Using this technique, 750 patients with suspected extracranial carotid artery disease were evaluated between January 1978 and January 1980. One hundred thirty-five of these 750 patients (18%) underwent cerebral arteriography performed with biplanar views of the carotid bifurcation. The degree of stenosis was measured independently in these patients and was available for comparison with the results of duplex scanning and spectral analysis. Duplex scanning correctly detected the presence of disease in 252 of 259 carotid arteries studied (97%). The extent of involvement varied from plaques that produced less than 10% diameter reduction to those that resulted in a total occlusion. The technique was less accurate with lesions that produced less than 10% diameter reduction.

Ultrasonic duplex scanning for disease of the carotid artery.

To determine the feasibility of quantitative ultrasonic techniques to define the composition of atherosclerotic plaques, samples of freshly excised human aortas were sewn to a sample holder and immersed in a saline bath for ultrasonic interrogation. Integrated backscatter of a 2-microsecond portion of the backscattered radiofrequency signal was measured with a 10 MHz focused transducer. Integrated backscatter was calculated by normalizing the root-mean-square voltage of the gated signal to the root-mean-square voltage obtained by replacing the tissue sample with a nearly perfect reflector. Microscopic examination of the 124 interrogated sites allowed differentiation of normal, fibrous, fibrofatty, and calcified regions. A site was considered calcified if it contained any histochemically detectable calcium. Values of integrated backscatter were markedly elevated from calcified regions (-30.0 +/- 6.4 dB, n = 25; mean +/- SD; p less than 0.001) compared to normal (-43.2 +/- 2.4 dB, n = 20) and fibrofatty (-43.9 +/- 3.4 dB, n = 43) sites. Values from fibrous regions (-40.7 +/- 3.8 dB, n = 36) were also significantly different compared with the calcified and fibrofatty regions (p less than 0.001). Thus, we have demonstrated that quantitative ultrasonic backscatter identifies and differentiates calcification and fibrosis in atherosclerotic sites offering promise for the noninvasive assessment of the pathologic status of the arterial wall.

Quantitative ultrasonic characterization of the nature of atherosclerotic plaques in human aorta.

Noninvasive diagnosis of renal artery stenosis by eeho-Doppler velocimetry

Carotid arterial disease in patients undergoing coronary artery bypass operations.

Ultrasound provides a convenient means for the clinical evaluation of both the anatomy and the blood velocity patterns in large peripheral blood vessels. Continued development of ultrasound techniques has reached the point of providing useful diagnostic information in a routine fashion. This paper describes the Duplex Scanner III, which provides B -mode images of vascular anatomy combined with a pulsed 5 MHz Doppler to analyze blood flow within those vessels imaged. Improvements over the Duplex Scanner II include: increased scan head reliability; additional operating features and processing techniques to more accurately evaluate anatomy and blood flow characteristics; and display and recording techniques to facilitate clinical use.

Detection of peripheral vascular disease using the Duplex Scanner III.

Non-invasive ultrasonic imaging of the carotid bifurcation by duplex scanning and ultrasonic arteriography combined with pulsed Doppler spectrum analysis demonstrated patency of the external and internal carotid arteries distal to a common carotid occlusion in 3 patients. Common carotid occlusion is not invariably associated with thrombosis of the ipsilateral internal carotid artery. Identification of internal carotid patency by the use of ultrasonic techniques will permit surgical treatment in selected cases.

K.C. Bodily

Papers

Detection of peripheral vascular disease using the Duplex Scanner III.

Ultrasonic demonstration of external and internal carotid patency with common carotid occlusion: a preliminary report.